While golf ball construction can vary greatly, most golf balls can be classified as either solid or wound. Solid golf balls include one-piece, two-piece, and multi-layer constructions. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by tensioned elastomeric material and a cover. By altering ball construction and composition, manufacturers can vary a wide range of playing characteristics, such as resilience, durability, spin, and “feel,” each of which can be optimized for various playing abilities.
By altering ball construction and composition, however, manufacturers can vary a wide range of characteristics, such as resilience, durability, spin, and “feel,” each of which can be optimized for various player abilities. In particular, the golf ball components that many manufacturers continually look to improve are the core, intermediate layers, if present, and covers.
Generally, golf ball cores and/or centers are constructed with a polybutadiene-based polymer composition. The properties of the polybutadiene composition are controlled by adjusting the cocktail of peroxides, curing agents, and fillers that are added.
Intermediate and, particularly, cover layers, while conventionally formed of ionomer-based materials, have, more recently, been formed of urethane-based materials, each having varying hardness and flexural moduli. Polyurethanes have become more preferred, especially for premium golf balls, because they have advantageous hardness and resilience properties compared to many ionomers. Conventional polyurethanes are typically formed from a prepolymer including a polyol and an isocyanate, and a curing agent. These polyurethanes, however, are still not ideal for golf ball layers—conventional prepolymer polyols and polyamines typically have a polydispersity (Mw/Mn, where Mw is the Weight Average Molecular Weight and Mn is the Number Average Molecular Weight) of at least 2.0 which can cause decreased impact strength and resiliency.
There remains a need, therefore, for improved polyurethane/urea hybrid compositions, especially those formed from unconventional starting materials, such as novel monodisperse (i.e., a polydispersity close to 1.0) heterotelechelic polymers (polymers having different functional groups on opposing termini, such as primary/secondary amine groups and hydroxyl groups), as well as hydrogenated and/or unprotected analogues thereof. The monodisperse, hydrophobic heterotelechelic diol/amines, and polyurethane/urea hybrids resulting therefrom, are suggested for use in a variety of golf ball constructions.